By Topic

Aerospace and Electronic Systems, IEEE Transactions on

Issue 3 • Date July 1998

Filter Results

Displaying Results 1 - 25 of 46
  • Comments on "Uncertainty ellipses and their applications to interval estimation of emitter position"

    Page(s): 979 - 980
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (166 KB)  

    The author comments on the work of L.R. Paradowski (ibid. vol. 33, p. 1, 1997) and points out some incorrect projections. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Comments on "Passive target tracking using maximum likelihood estimation"

    Page(s): 980 - 981
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (226 KB)  

    The author comments on the work of X.-J. Tao et al. (ibid. vol. 32, pp. 1348-54, 1996 and points out that some of the concepts introduced are debatable. This is backed up with some practical examples. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Comments on "Optimal guidance of proportional navigation"

    Page(s): 981 - 982
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (224 KB)  

    The author comments on the work of P.-J. Yuan (ibid. vol. 33, pp. 1007-1011, 1997) in which involved with the target motion parameters seem to have been ignored. In practice, the contact is obtained when the target tracking is on and target motion parameters (range, course, bearing, speed, and acceleration of the target) are found out. Various sophisticated versions of Kalman filter generate estimates with minimum variance. As long as the measurements are corrupted with noise, the estimates contain errors and these are described by covariance matrix of the estimated target state vector. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Comments on "A jerk model for tracking highly maneuvering targets" [with reply]

    Page(s): 982 - 983
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (207 KB)  

    The author comments on the work of K. Mehrotra & P.R. Mahapatra (ibid. vol. 33, pp. 1094-1105, 1997) who presented the derivation of covariance matrix of initial estimation of target state vector and the plant noise in detail. In their work the simulation and simulated results seem to be erroneous. Mehrotra replies to these comments. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Author's reply

    Page(s): 983
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (98 KB)  

    First Page of the Article
    View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Full text access may be available. Click article title to sign in or learn about subscription options.
  • Comments on "Estimation of singularities for intercept point forecasting"

    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (191 KB)  

    The author comments on an error in the work of A. Satish & R.I. Kashyap (ibid. vol. 32, pp. 1301-1310, 1996) who presented an algorithm for forecasting intercept point in passive target tracking. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Comments on "Canonical transform for tracking with kinematic models" and reply

    Page(s): 1014 - 1016
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (232 KB)  

    The author comments on the work of X. Rong Li (ibid. vol. 33, pp. 1212-24, 1997) in which it is mentioned that since the kinematic models are completely observable and controllable, the Kalman filter is stable and will converge to its steady state with a constant filter gain. Alternatively, a simpler implementation is to use directly a Kalman filter with the steady-state gain from the very beginning. It is contended that these statements are debatable. Rong Li replies to the comments. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Author's reply

    Page(s): 1015 - 1016
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (246 KB)  

    First Page of the Article
    View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Comments on "Properties and performance of extended target motion analysis" [with reply]

    Page(s): 1027 - 1032
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (199 KB)  

    The author comments on the work of J.P. Le Cadre & O. Tremois (ibid. vol. 32, pp. 66-82, 1996) in which they presented a simple initialization procedure useful for target motion analysis in highly nonlinear systems. However, for the implementation of K, the rate of spatial frequency, it is suggested that the assumptions made are not realistic. Le Cadre & Tremois reply to these comments. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Author's reply

    Page(s): 1028 - 1032
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (386 KB)  

    First Page of the Article
    View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • On-line identification of minimum-loss pulse patterns for resonant link converters

    Page(s): 1037 - 1043
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (580 KB)  

    In this paper we present a new procedure for the on-line identification of pulse patterns allowing loss minimization in fixed or varying loads fed by converters having outputs comprising discrete pulses, such as the resonant link converters. A control strategy based on it is developed and simulation results are compared with the true optimal ones and with those obtained by sigma-delta modulation View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Quick position determination using 1 or 2 LEO satellites

    Page(s): 736 - 754
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1456 KB)  

    We describe an approach for a medium accuracy position determination of a user terminal (UT) on the Earth surface, using one or two low Earth orbit (LEO) satellites. The positioning approach is intended to meet the requirements of a worldwide personal communications system using LEO satellites. The basic two requirements are: (1) immediate positioning, and (2) horizontal position accuracy of the order of 10 km. Those requirements stem from the need of the system to know the user's approximate location before it connects his call. The approach makes use of the two-way communication with the UT, which can receive, transmit, and make its own measurements. Delay and Doppler measurements are used in order to enable instantaneous positioning with one satellite, and in order to achieve unambiguous positioning with two satellites. A simplified Globalstar satellite constellation and the expected Globalstar delay and frequency measurement accuracy are used to demonstrate the concept and to evaluate its performances View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Adaptive A/D converter for improved DS/SS jam resistance

    Page(s): 810 - 816
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (660 KB)  

    The use of polar nonlinear processing to reject a constant carrier envelope (and possibly wideband) jammer of a DS/SS spread spectrum link is explored, with the additional objective of ensuring constant false alarm rate (CFAR) in the reception of the associated DS/SS synchronization preamble. It is shown that the constant carrier envelope jammer can be rejected very effectively, with CFAR, whether it is transmitted continuously or pulsed at some maximally damaging duty cycle View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • IMM tracking of maneuvering targets in the presence of glint

    Page(s): 996 - 1003
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (620 KB)  

    A problem of handling multiple types of discrete uncertainties (modes) in a dynamic system is addressed. The dynamic model for a target that exhibits maneuvers (one type of discrete uncertainty) and radar measurements that are perturbed by glint noise (another type of discrete uncertainty) is an example of such hybrid system with two independent mode sets. It is shown how an interacting multiple model (IMM) estimator can be efficiently designed for such systems. Doing the mixing step of the IMM in a number of layered stages, yields some computational savings when the mode sets are independent. Computer simulations are provided for two examples of maneuvering targets in the presence of glint. The results show that the IMM estimator with layered sets of models for glint and maneuver yields better performance (in terms of position and velocity root mean square error) compared with an IMM which handles maneuvers via multiple models and glint via nonlinear “score function” based filters View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Implementation of the simultaneous perturbation algorithm for stochastic optimization

    Page(s): 817 - 823
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (704 KB)  

    The need for solving multivariate optimization problems is pervasive in engineering and the physical and social sciences. The simultaneous perturbation stochastic approximation (SPSA) algorithm has recently attracted considerable attention for challenging optimization problems where it is difficult or impossible to directly obtain a gradient of the objective function with respect to the parameters being optimized. SPSA is based on an easily implemented and highly efficient gradient approximation that relies on measurements of the objective function, not on measurements of the gradient of the objective function. The gradient approximation is based on only two function measurements (regardless of the dimension of the gradient vector). This contrasts with standard finite-difference approaches, which require a number of function measurements proportional to the dimension of the gradient vector. This paper presents a simple step-by-step guide to implementation of SPSA in generic optimization problems and offers some practical suggestions for choosing certain algorithm coefficients View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A new fourth-order processing algorithm for spaceborne SAR

    Page(s): 824 - 835
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1184 KB)  

    A new fourth-order signal aperture radar (SAR) processing algorithm has been developed for a general satellite-Earth relative motion. The two-dimensional exact transfer function (ETF) is calculated and range-variant phase corrections have been calculated in order to process many azimuth lines per block. The ETF together with the phase corrections has been called the fourth-order EETF (extended ETF). It is also shown that a fourth-order EETF is necessary to process high quality images from spaceborne SAR with long integration times with spatial resolution around 1 m. The algorithm is fast and is anticipated to have good phase preservation properties View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Error analysis of direction cosines and quaternion parameters techniques for aircraft attitude determination

    Page(s): 983 - 989
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (448 KB)  

    Matrix differential equations for the determination of aircraft attitude orientation and the associated errors equations are developed in a four-dimensional space for both the direction cosines and quaternion parameter approaches. In this four-dimensional space, the corresponding algorithms, using accumulated gyro outputs, are developed and evaluated for the case of classical coning motion with time-varying angular velocity direction vector. Computation using symbolic algebra is considered in finding a closed-form solution for error propagation for a time-varying angular velocity direction vector. Examining the coning motion case shows that the true (analytic) scale and skew errors generated by the gyro drift are negligibly small in the direction cosines approach. Further, the true (analytic) scale errors in the quaternion technique are smaller than the computed (numerical) errors. Graphically illustrated are the true and computed errors in both the direction cosines and quaternion techniques for comparison View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • An intelligent landing system based on a human skill model

    Page(s): 877 - 882
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (592 KB)  

    An automatic landing system (ALS) is developed on the basis of a human skill model. The model is expressed as a nonlinear I/O mapping from the aircraft state to the control command provided by a human expert. In this system, all the I/O data provided by the human expert are stored in a database a priori, and a local model to answer the current aircraft state is built to generate a control input close to the human operation. A gain adaptation technique is introduced for improving the robustness View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Modeling of tracking loop noise and dynamics for efficient simulation of spread spectrum ranging systems

    Page(s): 1003 - 1008
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (448 KB)  

    The problem of efficiently simulating thermal noise and dynamic tracking errors in spread spectrum ranging receivers is addressed. A Gauss-Markov state space model is derived which simultaneously satisfies the conflicting requirements of high fidelity and fast-time operation. Initial validation results are presented View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Optimal observer maneuver for bearings-only tracking

    Page(s): 777 - 788
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (952 KB)  

    In bearings-only tracking, observer maneuver is critical to ensure observability and to obtain an accurate target localization. Here, optimal control theory is applied to the determination of the course of a constant speed observer that minimizes an accuracy criterion deduced from the Fisher information matrix (FIM). Necessary conditions for optimal maneuver (Euler equations) are established and resolved, partly by analytical means and partly by an iterative numerical procedure. Examples of optimal observer maneuvers are presented and discussed View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Autonomous fault detection and removal using GPS carrier phase

    Page(s): 897 - 906
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (980 KB)  

    This paper is focused on the use of carrier phase measurements and parity space methodology to investigate the limits of high-integrity and high-continuity satellite-based navigation performance. In this regard, a new algorithm for receiver autonomous fault detection and removal is developed with the specific goal of attaining the high levels of integrity and continuity required for aircraft precision approach and landing applications. Fault detection and removal algorithm performance is demonstrated through analysis and simulation, and the results of tests using deliberately induced failures in raw night data are presented View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A relative clutter metric

    Page(s): 968 - 976
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (684 KB)  

    Clutter plays a very important role in the area of machine and human-in-the-loop target acquisition. A great deal of interest has recently been shown in assessing several different definitions of clutter. In spite of so many definitions available, no single clutter definition has been agreed on by the infrared community as being the best. We develop a new clutter metric, called relative clutter, which is based on factor analysis which is extensively used for statistical analysis. This relative clutter combines many definitions of clutter. Different methods for calculating the relative clutter based on the magnitude of the eigenvalues obtained from the correlation matrix are suggested. The relative clutter of many images is analyzed View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Detection probability using relative clutter in infrared images

    Page(s): 955 - 962
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (920 KB)  

    Clutter plays a very important role in the area of machine and human-in-the-loop target acquisition. A great deal of interest has recently been shown in assessing several different definitions of clutter. In spite of so many definitions available, no single clutter definition has been agreed on by the target acquisition modeling community as being the best. Here we develop a new clutter metric, called relative clutter, based on factor analysis which is extensively used for statistical analysis. This relative clutter combines many definitions of clutter. Different methods for calculating the relative clutter based on the magnitude of the eigenvalues obtained from the correlation matrix are suggested. The relative clutter of many images is analyzed. The relative clutter is used to calculate probability of detection on Night Vision Lab (NVL) Terrain Board Infrared images View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Binary integration for Swerling target fluctuations

    Page(s): 1043 - 1053
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (528 KB)  

    Binary Integration is a suboptimal approach offering most of the benefits of integration with a simpler and less expensive receiver implementation than optimum coherent integration. We develop accurate, reliable, and efficient methods for binary integration computations for both the constant and Swerling target models. Binary integration introduces a new parameter M, the required number of threshold crossings to declare a detection. With these programs, we can readily do all the calculations necessary to determine the optimum values for M. We find that the assumed loss of 1.5 dB signal-to-noise ratio (SNR) per pulse for binary integration holds for small and large N, not only for the constant targets, but also for the Swerling target fluctuations View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.

Aims & Scope

IEEE Transactions on Aerospace and Electronic Systems focuses on the equipment, procedures, and techniques applicable to the organization, installation, and operation of functional systems designed to meet the high performance requirements of earth and space systems.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Lance Kaplan
Army Research Laboratory